Democrat Timothy M. Kaine has taken a narrow lead in Virginia's governor's race, buoyed by newfound strength in Northern Virginia's outer suburbs and an electorate turned off by what it considers the negative tone of his Republican opponent, according to a new Washington Post poll.

Kaine leads Republican Jerry W. Kilgore among the most likely voters by three percentage points, 47 to 44, according to the poll, which has a three percentage point margin of error. Independent candidate H. Russell Potts Jr. was supported by 4 percent of the voters.

The poll suggests a photo finish to a contest in which Kaine has cast himself as the logical successor to Democratic Gov. Mark R. Warner, who is barred from running for reelection. Kilgore has sought to define Kaine as a liberal who is out of touch with the state's conservative soul.

Kaine, the lieutenant governor and former mayor of Richmond, has tapped into Warner's sky-high popularity and enters the final stretch before the Nov. 8 election with momentum. But the governor's mansion is still within reach for the GOP, which holds solid majorities in the state legislature and closes strongly in statewide races.

The question for Kilgore, an ex-prosecutor and the state's former attorney general, is whether he can retake the lead in time, despite the political problems of his national party and President Bush.

"This is still a very, very close race. It's going to be a very late night on election night," said Kaine spokesman Mo Elleithee. "We feel very good about the momentum we are seeing. This confirms that people are not responding well to the slash-and-burn campaign that Jerry Kilgore is running."

Kilgore spokesman Tim Murtaugh challenged the results of the poll, which he called "slanted."

"The Washington Post poll has historically gone against Republican candidates," he said. "All of the polls have indicated that this is a close race, but we continue to believe that we have the lead."

Kaine improved his standing in the past 45 days. A Post poll conducted Sept. 6 to 9 showed the lieutenant governor trailing Kilgore by four percentage points among all voters and seven percentage points among likely voters.

Since then, Kaine has consolidated support among party loyalists and widened his lead among independents. He is besting Kilgore among women and older voters. He now leads among suburban voters, including the populous outer suburban communities of western Fairfax, Prince William and Loudoun counties.

Kilgore is leading among whites, men and those who say they live in rural areas. He also is favored by those who describe themselves as against abortion and for the death penalty.

Political observers said the challenge for both major-party candidates is to turn out their voters in a campaign that for a long time failed to stir passions. Kilgore is still in a strong position to win if he can woo some independents and undecided voters to his column.